For USGT class moving to LMH, we did that over a year back now, and it definitely has less interest than USGT had. I suspect people preferred a slightly slower class with tires what offered the grip level of the USGT tires, allowing the cars to push a little making the class very forgiving.to drivers with slower reaction times.
I think ROAR needs to re-examine dropping VTA and USGT from the rulebook, adopt them as regular classes instead of as exhibition classes, make sure they have two manufacturers for motors and tires of each so this isn't a one vendor class, and then drop LMH.